26639 Parietal Cell Antibodies, IgG, Serum (PCAB)

​​Gastric Parietal Cell

​Evaluating patients suspected of having pernicious anemia or autoimmune-mediated deficiency of vitamin B12 with or without megaloblastic anemia

​Centrifuge and aliquot serum into a plastic vial.

Gross hemolysis, Gross lipemia, Heat-treated specimen​

​​The presence of immune complexes or other immunoglobulin aggregates in the patient specimen may cause an increased nonspecific binding and produce false-positive results in this assay.

A negative result does not rule out the presence of parietal cell antibodies; the concentration of antibody may be below the detection limit of the assay.

A positive result only indicates the presence of antibody to H(+)/K(+) ATPase and does not necessarily indicate the presence of autoimmune disease or other diseases.

The assay performance has not been established for pediatric patients.​

Results of this assay should be used in conjunction with clinical findings and other serological tests.

The assay performance characteristics have not been established for matrices other than serum.

​Pernicious anemia (PA) is a common form of cobalamin (vitamin B12) deficiency anemia. The disorder is characterized by abnormally large (megaloblastic) red blood cells and atrophic body gastritis (ABG) resulting from autoimmune-mediated destruction of parietal cells that line the stomach wall. The destruction of parietal cells leads to impaired production of intrinsic factor (IF) required for the absorption of vitamin B12. PA is frequently associated with other autoimmune conditions, such as autoimmune thyroid disease, type 1 diabetes mellitus, and vitiligo. Diagnosis of PA relies on histologically proven ABG, peripheral blood examination showing megaloblastic anemia, vitamin B12 deficiency, parietal cell antibodies (PCA) with or without intrinsic factor antibodies (IFA), and elevated serum gastrin from loss of acid secretion. PCA bind to the alpha- and beta-subunits of the membrane-bound H(+)/K(+)-ATPase while IFA bind directly to intrinsic factor, blocking its ability to bind vitamin B12. Both PCA and IFA are useful diagnostic tests for PA, however, compared to PCA, IFA are more specific and lack diagnostic sensitivity.​

​A positive result indicates the presence of IgG antibodies to H(+)/K(+) ATPase and maybe suggestive of pernicious anemia (PA) or a related autoimmune disease.

A negative result indicates no detectable IgG antibodies to H(+)/K(+) ATPase; it does not rule out PA.

An equivocal result is inconclusive for the presence of IgG antibodies to H(+)/K(+)ATPase. Consider re-testing in 4-6 weeks if clinical suspicion for PA is high.